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https://issues.apache.org/jira/browse/SPARK-19742?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15906213#comment-15906213
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Navin Goel commented on SPARK-19742:
------------------------------------
Work around code in Java for anyone else ho is interested.
{code}
public void saveWithSchema(Dataset dataset, String tableName) {
dataset.selectExpr(getSchema(tableName,dataset)).write().insertInto(tableName);
}
private String[] getSchema(String table, Dataset ds) {
SparkSession spark = new SparkSession.Builder()
.master(settings().sparkMaster)
.appName(settings().sparkAppName)
.enableHiveSupport()
.getOrCreate();
Dataset tmp = spark.sql("select * from "+table+" limit 1");
String[] sourceColumns = ds.columns();
String[] targetColumns = tmp.columns();
String[] result = new String[targetColumns.length];
for (int i = 0; i < targetColumns.length; i++) {
String t = targetColumns[i];
if(containsCaseInsensitive(t, Arrays.asList(sourceColumns)))
result[i] = t;
else
result[i] = "null as "+t;
}
return result;
}
private static boolean containsCaseInsensitive(String s, List<String> l){
for (String string : l){
if (string.equalsIgnoreCase(s)){
return true;
}
}
return false;
}
{code}
> When using SparkSession to write a dataset to Hive the schema is ignored
> ------------------------------------------------------------------------
>
> Key: SPARK-19742
> URL: https://issues.apache.org/jira/browse/SPARK-19742
> Project: Spark
> Issue Type: Bug
> Components: Java API
> Affects Versions: 2.0.1
> Environment: Running on Ubuntu with HDP 2.4.
> Reporter: Navin Goel
>
> I am saving a Dataset that is created form reading a json and some selects
> and filters into a hive table. The dataset.write().insertInto function does
> not look at schema when writing to the table but instead writes in order to
> the hive table.
> The schemas for both the tables are same.
> schema printed from spark of the dataset being written:
> StructType(StructField(countrycode,StringType,true),
> StructField(systemflag,StringType,true),
> StructField(classcode,StringType,true),
> StructField(classname,StringType,true),
> StructField(rangestart,StringType,true),
> StructField(rangeend,StringType,true),
> StructField(tablename,StringType,true),
> StructField(last_updated_date,TimestampType,true))
> Schema of the dataset after loading the same table from Hive:
> StructType(StructField(systemflag,StringType,true),
> StructField(RangeEnd,StringType,true),
> StructField(classcode,StringType,true),
> StructField(classname,StringType,true),
> StructField(last_updated_date,TimestampType,true),
> StructField(countrycode,StringType,true),
> StructField(rangestart,StringType,true),
> StructField(tablename,StringType,true))
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